Smash Wii U Frames and auto cancel

[Jinxedmerphit]

New to the board but not new to smash.
Recently I have been looking at the frame data information from several different sources, and have run in to some confusion, and it would be great if some one could fill me in on what I am missing.

Just to explain I get the idea of how auto cancelling works, and with some moves you fast fall during x/y frames in order to reduce or mitigate the landing lag.

However when looking at the frame data I kind of expected it to say the frames in which you can cancel.
to give an example: Greninja's Nair my understanding is you can auto cancel it, and I am fairly sure I am able to do it.
However information taken from kuroganehammer website: start up frames: 12-13 for the first hit box? and the auto cancel window is between the first 1-9 frames, or after 40 frames.
If this is correct then it auto cancels before the hurt box?
I am sure I am missing something, as this is my first time really looking at frame data I am not 100% sure I am reading it correctly, so any help that any one can offer would be greatly appreciated.

Also if this has been answered else were, I have looked but could not find any thing specifically about this question, found plenty of information about frame data and how understand other bits and bobs though

 

[Nah]

Yeah, a lot of aerials have autocancel windows before the hitbox even comes out. If Greninja lands between frames 1-9 of Nair, it will just incur the normal lag for just plain landing of 2 or 4 frames (I'm not sure which it is for autocancels). If you land between frames 10-39, it'll incur Nair's usual landing lag of 12 frames. If you land between frames 40-64 (Greninja's Nair has a total duration of 64 frames) it'll autocancel. Does this help at all, I'm not entirely sure what it is you're asking?

 

[Jinxedmerphit]

ok I get that, but I am sure people have said and there are combo's that rely on auto cancelling it during the frames in which the hit box is coming out? like the nair fast fall, foot stall, is that really during the normal 12 frames? and is it just the 64 frames of the nair you are cancelling?
also one the other moves I was looking at is c'falcons back air, that can apparently be auto cancelled leading to follow ups, but again the frame data suggests there is frame during the hit box that you can remove the landing lag.

If this is the case I guess I have just been miss understanding the point of auto cancelling and it is not to cancel landing lag, but in fact to cancel the full "FAF" of what ever move you are using?

 

[Nah]

Landing already "cancels" the FAF (ie Greninja will no longer be Nairing when it hits the ground). Autocanceling then greatly lessens the landing lag of that particular move on top of that. It's the landing lag of an aerial that can make it unsafe/not allow for follow-ups, but autocanceling then all but removes that landing lag, which is why it's so valuable.

Doing it in training mode might help you.